package com.kingsoft.dc.khaos.extender.meta.utils;

import javax.crypto.Cipher;
import javax.crypto.spec.OAEPParameterSpec;
import javax.crypto.spec.PSource;
import java.io.ByteArrayOutputStream;
import java.io.UnsupportedEncodingException;
import java.security.Key;
import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.spec.MGF1ParameterSpec;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

public class RSAEncrypt {

    public static final String RSA_ALGORITHM = "RSA/ECB/OAEPWithSHA-256AndMGF1Padding";
    public static final String ENDCODE = "UTF-8";
    /**
     * 加密分段位数
     */
    public static final int MAX_ENCRYPT_BLOCK = 62;
    /**
     * 解密分段位数
     */
    public static final int MAX_DECRYPT_BLOCK = 128;


    public static final String privateKey = "MIICdgIBADANBgkqhkiG9w0BAQEFAASCA" +
            "mAwggJcAgEAAoGBAKBDuEe2JJyi4T2C83GM42KPqeGov6O9KkCdePmerXwjtVdQP5" +
            "De6BDE5uqso108Rd4awHXeaCrtsx2zmBQyyH0nWx1Z95xV03qdnP6Mf9+ufOIzJTD" +
            "VTcOJ1WYNevnnlCXltiJ0X85hZPtITRipEYwuWrfimgTiNHVh0dCzu5IJAgMBAAEC" +
            "gYAH8VNAupY17Rycn9DQ39qlF9mjhWl6A/YEHcnRFTwj2uEx4phD5cg6jIelOcke5" +
            "c3QpCLFtLAU8JLf9fajiaDF/wUwuqVwyg6aWnaA8RNpIR0ITBUJ/ZUQSTmSIotAjz" +
            "6uU/rRrZHwhygRGVx+oySLp5D2FtmU2X8H+uB8csLiwQJBANMRnbSpNcWhTNd95vN" +
            "zX+pkBALTF6kFOFhpoWI/TH9ppCJIasE1nUcXwCpoEZ1lOXY6n8avRTRynnw3BS7M" +
            "vvMCQQDCYXqdQONzPS5SCME/KzjJ6roo9tJYfvA28xHmtcIEmaxuNwuIALnYDEPU8" +
            "QIHo5cfzQwkxUFT6hPouHvQpoITAkEAzm8yUZoVr399Sl4nXgB/1R2RFrojL/qdC0" +
            "v0vcSvKwbFs4okb2fitb+zAUbbw5dXRh08W/TcuNlJzK97cDRspQJANaI19dvopmx" +
            "0Mnht8eMYKUaWFSV9hqOH3nGVN+Zg4WoRlNulV+JzZPSFZuUVHUx7L3AhcKfozaGh" +
            "2q3EpB69dwJAeFfu5IISQxlhR6ziU4cU/U3QCB5TgcF2pXYl+DkHBliHpCdtoNg2J" +
            "Ov8ElcDvYRiWsLmM49Dn4TTA3QK7psgqg==";

    //数据源登录密码解密操作
    public static String decryptByRSAPassWord(String rsaPassWord) throws Exception {
        String passWord = RSAEncrypt.decrypt(privateKey, rsaPassWord);
        return passWord;
    }
    //公钥和私钥必须是PKCS8格式

    /**
     * 加密方法
     *
     * @param publicKey 公钥
     * @param raw       待加密明文
     * @return 加密后的密文
     * @throws Exception
     */
    public static String encrypt(String publicKey, String raw) throws Exception {
        return new String(encrypt(publicKey, raw.getBytes(ENDCODE)), ENDCODE);
    }

    /**
     * 加密方法
     *
     * @param publicKey 公钥
     * @param raw       待加密明文
     * @return 加密后的密文
     * @throws Exception
     */
    public static byte[] encrypt(String publicKey, byte[] raw) throws Exception {
        Key key = getPublicKey(publicKey);
        Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, key, new OAEPParameterSpec("SHA-256", "MGF1", MGF1ParameterSpec.SHA256,
                PSource.PSpecified.DEFAULT));
        byte[] encryptedData = doBySlice(cipher, raw, MAX_ENCRYPT_BLOCK);
        return Base64.encodeBase64(encryptedData);
    }


    /**
     * 分段处理方法
     * @param cipher
     * @param data
     * @param MAX_BLOCK
     * @return
     * @throws Exception
     */
    public static byte[] doBySlice(Cipher cipher,byte[] data,int MAX_BLOCK) throws Exception{
        int inputLen =  data.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_BLOCK) {
                cache = cipher.doFinal(data, offSet, MAX_BLOCK);
            } else {
                cache = cipher.doFinal(data, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_BLOCK;
        }
        byte[] encryptedData = out.toByteArray();
        out.close();
        return encryptedData;
    }

    /**
     * 解密方法
     *
     * @param privateKey 私钥
     * @param enc        待解密密文
     * @return 解密后的明文
     * @throws Exception
     */
    public static String decrypt(String privateKey, String enc) throws Exception {
        return new String(decrypt(privateKey, enc.getBytes(ENDCODE)), ENDCODE);
    }

    /**
     * 解密方法
     *
     * @param privateKey 私钥
     * @param enc        待解密密文
     * @return 解密后的明文
     * @throws Exception
     */
    public static byte[] decrypt(String privateKey, byte[] enc) throws Exception {
        Key key = getPrivateKey(privateKey);
        Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, key, new OAEPParameterSpec("SHA-256", "MGF1", MGF1ParameterSpec.SHA256,
                PSource.PSpecified.DEFAULT));
        byte[] data = Base64.decodeBase64(enc);
        return doBySlice(cipher,data,MAX_DECRYPT_BLOCK);
    }


    /**
     * 旧加密（不能超过62位明文）
     * @param publicKey
     * @param raw
     * @return
     * @throws Exception
     */
    @Deprecated
    public static String encryptOld(String publicKey, String raw) throws Exception {
        return new String(encryptOld(publicKey, raw.getBytes(ENDCODE)), ENDCODE);
    }

    /**
     * 旧解密
     * @param privateKey
     * @param enc
     * @return
     * @throws Exception
     */
    @Deprecated
    public static String decryptOld(String privateKey, String enc) throws Exception {
        return new String(decryptOld(privateKey, enc.getBytes(ENDCODE)), ENDCODE);
    }

    /**
     * 旧加密（不能超过62位明文）
     *
     * @param publicKey 公钥
     * @param raw       待加密明文
     * @return 加密后的密文
     * @throws Exception
     */
    @Deprecated
    public static byte[] encryptOld(String publicKey, byte[] raw) throws Exception {
        Key key = getPublicKey(publicKey);
        Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, key, new OAEPParameterSpec("SHA-256", "MGF1", MGF1ParameterSpec.SHA256,
                PSource.PSpecified.DEFAULT));
        return Base64.encodeBase64(cipher.doFinal(raw));
    }

    /**
     * 旧解密
     * @param privateKey
     * @param enc
     * @return
     * @throws Exception
     */
    @Deprecated
    public static byte[] decryptOld(String privateKey, byte[] enc) throws Exception {
        Key key = getPrivateKey(privateKey);
        Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, key, new OAEPParameterSpec("SHA-256", "MGF1", MGF1ParameterSpec.SHA256,
                PSource.PSpecified.DEFAULT));
        return cipher.doFinal(Base64.decodeBase64(enc));
    }

    /**
     * 获取公钥
     *
     * @param key 密钥字符串（经过base64编码）
     * @return 公钥
     * @throws Exception
     */
    public static PublicKey getPublicKey(String key) throws Exception {
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(Base64.decodeBase64(key.getBytes()));
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PublicKey publicKey = keyFactory.generatePublic(keySpec);
        return publicKey;
    }

    /**
     * 获取私钥
     *
     * @param key 密钥字符串（经过base64编码）
     * @return 私钥
     * @throws Exception
     */
    public static PrivateKey getPrivateKey(String key) throws Exception {
        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(Base64.decodeBase64(key.getBytes()));
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PrivateKey privateKey = keyFactory.generatePrivate(keySpec);
        return privateKey;
    }

    /**
     * 获取私钥
     * @return 私钥
     * @throws Exception
     */
    public static String getPK() throws Exception {
        return privateKey;
    }

}

class Base64 {
    /**
     * Chunk size per RFC 2045 section 6.8.
     * <p>
     * <p>The {@value} character limit does not count the trailing CRLF, but counts
     * all other characters, including any equal signs.</p>
     *
     * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 6.8</a>
     */
    static final int CHUNK_SIZE = 76;

    /**
     * Chunk separator per RFC 2045 section 2.1.
     *
     * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 2.1</a>
     */
    static final byte[] CHUNK_SEPARATOR = "\r\n".getBytes();

    /**
     * The base length.
     */
    static final int BASELENGTH = 255;

    /**
     * Lookup length.
     */
    static final int LOOKUPLENGTH = 64;

    /**
     * Used to calculate the number of bits in a byte.
     */
    static final int EIGHTBIT = 8;

    /**
     * Used when encoding something which has fewer than 24 bits.
     */
    static final int SIXTEENBIT = 16;

    /**
     * Used to determine how many bits data contains.
     */
    static final int TWENTYFOURBITGROUP = 24;

    /**
     * Used to get the number of Quadruples.
     */
    static final int FOURBYTE = 4;

    /**
     * Used to test the sign of a byte.
     */
    static final int SIGN = -128;

    /**
     * Byte used to pad output.
     */
    static final byte PAD = (byte) '=';

    // Create arrays to hold the base64 characters and a
    // lookup for base64 chars
    private static byte[] base64Alphabet = new byte[BASELENGTH];
    private static byte[] lookUpBase64Alphabet = new byte[LOOKUPLENGTH];

    // Populating the lookup and character arrays
    static {
        for (int i = 0; i < BASELENGTH; i++) {
            base64Alphabet[i] = (byte) -1;
        }
        for (int i = 'Z'; i >= 'A'; i--) {
            base64Alphabet[i] = (byte) (i - 'A');
        }
        for (int i = 'z'; i >= 'a'; i--) {
            base64Alphabet[i] = (byte) (i - 'a' + 26);
        }
        for (int i = '9'; i >= '0'; i--) {
            base64Alphabet[i] = (byte) (i - '0' + 52);
        }

        base64Alphabet['+'] = 62;
        base64Alphabet['/'] = 63;

        for (int i = 0; i <= 25; i++) {
            lookUpBase64Alphabet[i] = (byte) ('A' + i);
        }

        for (int i = 26, j = 0; i <= 51; i++, j++) {
            lookUpBase64Alphabet[i] = (byte) ('a' + j);
        }

        for (int i = 52, j = 0; i <= 61; i++, j++) {
            lookUpBase64Alphabet[i] = (byte) ('0' + j);
        }

        lookUpBase64Alphabet[62] = (byte) '+';
        lookUpBase64Alphabet[63] = (byte) '/';
    }

    private static boolean isBase64(byte octect) {
        if (octect == PAD) {
            return true;
        } else if (base64Alphabet[octect] == -1) {
            return false;
        } else {
            return true;
        }
    }

    /**
     * Tests a given byte array to see if it contains
     * only valid characters within the Base64 alphabet.
     *
     * @param arrayOctect byte array to test
     * @return true if all bytes are valid characters in the Base64
     * alphabet or if the byte array is empty; false, otherwise
     */
    public static boolean isArrayByteBase64(byte[] arrayOctect) {

        arrayOctect = discardWhitespace(arrayOctect);

        int length = arrayOctect.length;
        if (length == 0) {
            // shouldn't a 0 length array be valid base64 data?
            // return false;
            return true;
        }
        for (int i = 0; i < length; i++) {
            if (!isBase64(arrayOctect[i])) {
                return false;
            }
        }
        return true;
    }

    /**
     * Encodes binary data using the base64 algorithm but
     * does not chunk the output.
     *
     * @param binaryData binary data to encode
     * @return Base64 characters
     */
    public static byte[] encodeBase64(byte[] binaryData) {
        return encodeBase64(binaryData, false);
    }

    /**
     * Encodes binary data using the base64 algorithm and chunks
     * the encoded output into 76 character blocks
     *
     * @param binaryData binary data to encode
     * @return Base64 characters chunked in 76 character blocks
     */
    public static byte[] encodeBase64Chunked(byte[] binaryData) {
        return encodeBase64(binaryData, true);
    }

    /**
     * Decodes a byte[] containing containing
     * characters in the Base64 alphabet.
     *
     * @param pArray A byte array containing Base64 character data
     * @return a byte array containing binary data
     */
    public static byte[] decode(byte[] pArray) {
        return decodeBase64(pArray);
    }

    /**
     * Encodes binary data using the base64 algorithm, optionally
     * chunking the output into 76 character blocks.
     *
     * @param binaryData Array containing binary data to encode.
     * @param isChunked  if isChunked is true this encoder will chunk
     *                   the base64 output into 76 character blocks
     * @return Base64-encoded data.
     */
    public static byte[] encodeBase64(byte[] binaryData, boolean isChunked) {
        int lengthDataBits = binaryData.length * EIGHTBIT;
        int fewerThan24bits = lengthDataBits % TWENTYFOURBITGROUP;
        int numberTriplets = lengthDataBits / TWENTYFOURBITGROUP;
        byte encodedData[] = null;
        int encodedDataLength = 0;
        int nbrChunks = 0;

        if (fewerThan24bits != 0) {
            //data not divisible by 24 bit
            encodedDataLength = (numberTriplets + 1) * 4;
        } else {
            // 16 or 8 bit
            encodedDataLength = numberTriplets * 4;
        }

        // If the output is to be "chunked" into 76 character sections,
        // for compliance with RFC 2045 MIME, then it is important to
        // allow for extra length to account for the separator(s)
        if (isChunked) {

            nbrChunks =
                    (CHUNK_SEPARATOR.length == 0 ? 0 : (int) Math.ceil((float) encodedDataLength / CHUNK_SIZE));
            encodedDataLength += nbrChunks * CHUNK_SEPARATOR.length;
        }

        encodedData = new byte[encodedDataLength];

        byte k = 0, l = 0, b1 = 0, b2 = 0, b3 = 0;

        int encodedIndex = 0;
        int dataIndex = 0;
        int i = 0;
        int nextSeparatorIndex = CHUNK_SIZE;
        int chunksSoFar = 0;

        //log.debug("number of triplets = " + numberTriplets);
        for (i = 0; i < numberTriplets; i++) {
            dataIndex = i * 3;
            b1 = binaryData[dataIndex];
            b2 = binaryData[dataIndex + 1];
            b3 = binaryData[dataIndex + 2];

            //log.debug("b1= " + b1 +", b2= " + b2 + ", b3= " + b3);

            l = (byte) (b2 & 0x0f);
            k = (byte) (b1 & 0x03);

            byte val1 =
                    ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);
            byte val2 =
                    ((b2 & SIGN) == 0) ? (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0);
            byte val3 =
                    ((b3 & SIGN) == 0) ? (byte) (b3 >> 6) : (byte) ((b3) >> 6 ^ 0xfc);

            encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
            //log.debug( "val2 = " + val2 );
            //log.debug( "k4   = " + (k<<4) );
            //log.debug(  "vak  = " + (val2 | (k<<4)) );
            encodedData[encodedIndex + 1] =
                    lookUpBase64Alphabet[val2 | (k << 4)];
            encodedData[encodedIndex + 2] =
                    lookUpBase64Alphabet[(l << 2) | val3];
            encodedData[encodedIndex + 3] = lookUpBase64Alphabet[b3 & 0x3f];

            encodedIndex += 4;

            // If we are chunking, let's put a chunk separator down.
            if (isChunked) {
                // this assumes that CHUNK_SIZE % 4 == 0
                if (encodedIndex == nextSeparatorIndex) {
                    System.arraycopy(
                            CHUNK_SEPARATOR,
                            0,
                            encodedData,
                            encodedIndex,
                            CHUNK_SEPARATOR.length);
                    chunksSoFar++;
                    nextSeparatorIndex =
                            (CHUNK_SIZE * (chunksSoFar + 1)) +
                                    (chunksSoFar * CHUNK_SEPARATOR.length);
                    encodedIndex += CHUNK_SEPARATOR.length;
                }
            }
        }

        // form integral number of 6-bit groups
        dataIndex = i * 3;

        if (fewerThan24bits == EIGHTBIT) {
            b1 = binaryData[dataIndex];
            k = (byte) (b1 & 0x03);
            //log.debug("b1=" + b1);
            //log.debug("b1<<2 = " + (b1>>2) );
            byte val1 =
                    ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);
            encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
            encodedData[encodedIndex + 1] = lookUpBase64Alphabet[k << 4];
            encodedData[encodedIndex + 2] = PAD;
            encodedData[encodedIndex + 3] = PAD;
        } else if (fewerThan24bits == SIXTEENBIT) {

            b1 = binaryData[dataIndex];
            b2 = binaryData[dataIndex + 1];
            l = (byte) (b2 & 0x0f);
            k = (byte) (b1 & 0x03);

            byte val1 =
                    ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);
            byte val2 =
                    ((b2 & SIGN) == 0) ? (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0);

            encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
            encodedData[encodedIndex + 1] =
                    lookUpBase64Alphabet[val2 | (k << 4)];
            encodedData[encodedIndex + 2] = lookUpBase64Alphabet[l << 2];
            encodedData[encodedIndex + 3] = PAD;
        }

        if (isChunked) {
            // we also add a separator to the end of the final chunk.
            if (chunksSoFar < nbrChunks) {
                System.arraycopy(
                        CHUNK_SEPARATOR,
                        0,
                        encodedData,
                        encodedDataLength - CHUNK_SEPARATOR.length,
                        CHUNK_SEPARATOR.length);
            }
        }

        return encodedData;
    }

    /**
     * Decodes Base64 data into octects
     *
     * @param base64Data Byte array containing Base64 data
     * @return Array containing decoded data.
     */
    public static byte[] decodeBase64(byte[] base64Data) {
        // RFC 2045 requires that we discard ALL non-Base64 characters
        base64Data = discardNonBase64(base64Data);

        // handle the edge case, so we don't have to worry about it later
        if (base64Data.length == 0) {
            return new byte[0];
        }

        int numberQuadruple = base64Data.length / FOURBYTE;
        byte decodedData[] = null;
        byte b1 = 0, b2 = 0, b3 = 0, b4 = 0, marker0 = 0, marker1 = 0;

        // Throw away anything not in base64Data

        int encodedIndex = 0;
        int dataIndex = 0;
        {
            // this sizes the output array properly - rlw
            int lastData = base64Data.length;
            // ignore the '=' padding
            while (base64Data[lastData - 1] == PAD) {
                if (--lastData == 0) {
                    return new byte[0];
                }
            }
            decodedData = new byte[lastData - numberQuadruple];
        }

        for (int i = 0; i < numberQuadruple; i++) {
            dataIndex = i * 4;
            marker0 = base64Data[dataIndex + 2];
            marker1 = base64Data[dataIndex + 3];

            b1 = base64Alphabet[base64Data[dataIndex]];
            b2 = base64Alphabet[base64Data[dataIndex + 1]];

            if (marker0 != PAD && marker1 != PAD) {
                //No PAD e.g 3cQl
                b3 = base64Alphabet[marker0];
                b4 = base64Alphabet[marker1];

                decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
                decodedData[encodedIndex + 1] =
                        (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
                decodedData[encodedIndex + 2] = (byte) (b3 << 6 | b4);
            } else if (marker0 == PAD) {
                //Two PAD e.g. 3c[Pad][Pad]
                decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
            } else if (marker1 == PAD) {
                //One PAD e.g. 3cQ[Pad]
                b3 = base64Alphabet[marker0];

                decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
                decodedData[encodedIndex + 1] =
                        (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
            }
            encodedIndex += 3;
        }
        return decodedData;
    }

    /**
     * Discards any whitespace from a base-64 encoded block.
     *
     * @param data The base-64 encoded data to discard the whitespace
     *             from.
     * @return The data, less whitespace (see RFC 2045).
     */
    static byte[] discardWhitespace(byte[] data) {
        byte groomedData[] = new byte[data.length];
        int bytesCopied = 0;

        for (int i = 0; i < data.length; i++) {
            switch (data[i]) {
                case (byte) ' ':
                case (byte) '\n':
                case (byte) '\r':
                case (byte) '\t':
                    break;
                default:
                    groomedData[bytesCopied++] = data[i];
            }
        }

        byte packedData[] = new byte[bytesCopied];

        System.arraycopy(groomedData, 0, packedData, 0, bytesCopied);

        return packedData;
    }

    /**
     * Discards any characters outside of the base64 alphabet, per
     * the requirements on page 25 of RFC 2045 - "Any characters
     * outside of the base64 alphabet are to be ignored in base64
     * encoded data."
     *
     * @param data The base-64 encoded data to groom
     * @return The data, less non-base64 characters (see RFC 2045).
     */
    static byte[] discardNonBase64(byte[] data) {
        byte groomedData[] = new byte[data.length];
        int bytesCopied = 0;

        for (int i = 0; i < data.length; i++) {
            if (isBase64(data[i])) {
                groomedData[bytesCopied++] = data[i];
            }
        }

        byte packedData[] = new byte[bytesCopied];

        System.arraycopy(groomedData, 0, packedData, 0, bytesCopied);

        return packedData;
    }

    /**
     * Encodes a byte[] containing binary data, into a byte[] containing
     * characters in the Base64 alphabet.
     *
     * @param pArray a byte array containing binary data
     * @return A byte array containing only Base64 character data
     */
    public static byte[] encode(byte[] pArray) {
        return encodeBase64(pArray, false);
    }

    public static String encode(String str) throws UnsupportedEncodingException {
        String baseStr = new String(encode(str.getBytes("UTF-8")));
        String tempStr = digest(str).toUpperCase();
        String result = tempStr + baseStr;
        return new String(encode(result.getBytes("UTF-8")));
    }

    public static String decode(String cryptoStr) throws
            UnsupportedEncodingException {
        if (cryptoStr.length() < 40)
            return "";
        try {
            String tempStr = new String(decode(cryptoStr.getBytes("UTF-8")));
            String result = tempStr.substring(40, tempStr.length());
            return new String(decode(result.getBytes("UTF-8")));
        } catch (ArrayIndexOutOfBoundsException ex) {
            return "";
        }
    }

    /**
     * Decodes Base64 data into octects
     *
     * @param encoded string containing Base64 data
     * @return Array containind decoded data.
     */
    public static byte[] decode2(String encoded) {

        if (encoded == null) {
            return null;
        }

        char[] base64Data = encoded.toCharArray();
        // remove white spaces
        int len = removeWhiteSpace(base64Data);

        if (len % FOURBYTE != 0) {
            return null;//should be divisible by four
        }

        int numberQuadruple = (len / FOURBYTE);

        if (numberQuadruple == 0) {
            return new byte[0];
        }

        byte decodedData[] = null;
        byte b1 = 0, b2 = 0, b3 = 0, b4 = 0;
        char d1 = 0, d2 = 0, d3 = 0, d4 = 0;

        int i = 0;
        int encodedIndex = 0;
        int dataIndex = 0;
        decodedData = new byte[(numberQuadruple) * 3];

        for (; i < numberQuadruple - 1; i++) {

            if (!isData((d1 = base64Data[dataIndex++])) || !isData((d2 = base64Data[dataIndex++]))
                    || !isData((d3 = base64Data[dataIndex++]))
                    || !isData((d4 = base64Data[dataIndex++]))) {
                return null;
            }//if found "no data" just return null

            b1 = base64Alphabet[d1];
            b2 = base64Alphabet[d2];
            b3 = base64Alphabet[d3];
            b4 = base64Alphabet[d4];

            decodedData[encodedIndex++] = (byte) (b1 << 2 | b2 >> 4);
            decodedData[encodedIndex++] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
            decodedData[encodedIndex++] = (byte) (b3 << 6 | b4);
        }

        if (!isData((d1 = base64Data[dataIndex++])) || !isData((d2 = base64Data[dataIndex++]))) {
            return null;//if found "no data" just return null
        }

        b1 = base64Alphabet[d1];
        b2 = base64Alphabet[d2];

        d3 = base64Data[dataIndex++];
        d4 = base64Data[dataIndex++];
        if (!isData((d3)) || !isData((d4))) {//Check if they are PAD characters
            if (isPad(d3) && isPad(d4)) {
                if ((b2 & 0xf) != 0)//last 4 bits should be zero
                {
                    return null;
                }
                byte[] tmp = new byte[i * 3 + 1];
                System.arraycopy(decodedData, 0, tmp, 0, i * 3);
                tmp[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
                return tmp;
            } else if (!isPad(d3) && isPad(d4)) {
                b3 = base64Alphabet[d3];
                if ((b3 & 0x3) != 0)//last 2 bits should be zero
                {
                    return null;
                }
                byte[] tmp = new byte[i * 3 + 2];
                System.arraycopy(decodedData, 0, tmp, 0, i * 3);
                tmp[encodedIndex++] = (byte) (b1 << 2 | b2 >> 4);
                tmp[encodedIndex] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
                return tmp;
            } else {
                return null;
            }
        } else { //No PAD e.g 3cQl
            b3 = base64Alphabet[d3];
            b4 = base64Alphabet[d4];
            decodedData[encodedIndex++] = (byte) (b1 << 2 | b2 >> 4);
            decodedData[encodedIndex++] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
            decodedData[encodedIndex++] = (byte) (b3 << 6 | b4);

        }

        return decodedData;
    }

    private static boolean isWhiteSpace(char octect) {
        return (octect == 0x20 || octect == 0xd || octect == 0xa || octect == 0x9);
    }

    private static boolean isData(char octect) {
        return (octect < BASELENGTH && base64Alphabet[octect] != -1);
    }

    private static boolean isPad(char octect) {
        return (octect == PAD);
    }

    /**
     * remove WhiteSpace from MIME containing encoded Base64 data.
     *
     * @param data the byte array of base64 data (with WS)
     * @return the new length
     */
    private static int removeWhiteSpace(char[] data) {
        if (data == null) {
            return 0;
        }

        // count characters that's not whitespace
        int newSize = 0;
        int len = data.length;
        for (int i = 0; i < len; i++) {
            if (!isWhiteSpace(data[i])) {
                data[newSize++] = data[i];
            }
        }
        return newSize;
    }

    public static final String ENCODE = "UTF-8";

    public static String digest(String aValue) {
        return digest(aValue, ENCODE);

    }

    public static String digest(String aValue, String encoding) {
        aValue = aValue.trim();
        byte value[];
        try {
            value = aValue.getBytes(encoding);
        } catch (UnsupportedEncodingException e) {
            value = aValue.getBytes();
        }
        MessageDigest md = null;
        try {
            md = MessageDigest.getInstance("SHA");
        } catch (NoSuchAlgorithmException e) {
            return null;
        }
        return toHex(md.digest(value));
    }

    public static String toHex(byte input[]) {
        if (input == null)
            return null;
        StringBuffer output = new StringBuffer(input.length * 2);
        for (int i = 0; i < input.length; i++) {
            int current = input[i] & 0xff;
            if (current < 16)
                output.append("0");
            output.append(Integer.toString(current, 16));
        }

        return output.toString();
    }
}